Katie Couric's Notebook: Please Rob Me

If you're on Facebook, Twitter or Foursquare, you've seen them: a friend posts about the sushi she's eating right now at a favorite restaurant ... or worse ... tweets about boarding a plane for vacation.

While that may seem like a little innocent fun, a new web site with a blunt name shows the dark side. Please rob me-dot-com puts that kind of information in one place and tells the world when you're not at home.

Now, it seems unlikely this could serve as a burglar's guide, but that's not the point. We've become so used to sharing personal information online, we tend to forget to think twice.

There are plenty of people who have literally thousands of Facebook friends. And they can't possibly know them all. And with Twitter, there's no telling who's following your every move.

Some of these people may not exactly have your best interests in mind ... and with friends like those ... Who needs enemies?

That's a page from my notebook.

I'm Katie Couric, CBS News.